Air-spring.



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MPPLICMION FILED SEPT. i916.

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. R. GRUSS.

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APMM/mom FILED SEPT. e, |916.

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LUCIEN R. GRUSS,`O`F SANFRANGISCO, CALlFORNIA, ASSIGNOR TO PNEUMATC CUSHION' C0., OF SANIFRANGISCO, CALIFORNIA, A CORPORATION `015 CALIFORNIA.

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Application led September 6,1916. Serial No. 118,627.

To all whom t may concern.'

Be it known that I, LUCIEN R. GRUss, a` citizen of the United States, .residing in the city and county vof San Francisco and State of Californizuhave invented new and useful improvements in Air-Sprin`gs, of which the following is a specification.

This invention relates to pneumatic cus ions of the type shown and described in my .prior Patent No. 1,142,162, dated June 8,

The inventionis designed particularly for use on heavyl pleasure cars, auto trucks, and

. other vehicles for the 'purpose of :giving the desired degree of resiliency and freedom from shock andy vibration when traveling over rough roads and obstructions; this air spring being' used in conjunction with or in lieu of the ordinary metal springs 4with which the car or truck, or other vehicle may already be equipped.

l The present invention embodies essentially a pair of telescoping cylinders divided by a valveless piston carried by one cylinder having a sliding fit in the other; the space .above the piston forming a cushion chamber containing the elastic medium like air, and also containing an oil seal against air leakage;

- the lower space Vor chamber containing a surplus of oil andlubricating the sliding joint between the two cylinders; no provision being made against the escape oi any oil thatmay pass this sliding joint.

The chief function of the lower chamber.

or the chamber below the solid piston is that of a recoil check.

With the apparatus at rest and vsupporting its load, there is normally no pressure in the lower chamber. By reason of this peculiar construction of air spring in which a partitioning piston is employed, provision is made against excessive elongation of the air spring as occurs where two cylinders confine a cushioning lmedium in a single chamber.

Such a construction ofa single chamber without its 'partitioning piston result-s in producing such a degree of elasticity andV rebound as to render the use of such springs dangerous in rounding curves o r in traveling over rough roads at high speed.

Having reference to the accompanying drawings: i n v Figure 1 is a side elevation-in partial section (the inner cylinder being shown in elevation) showing the rear end connection.

Fig. 2 isa View of the saine spring in partial section at'right` angles to the position shown in-Fig. 1.

` Fig. 3 is a vertical section of the front spring and its connection with thefront end of the vehicle.

Fig. L.Lis a section on line 4 4 of Fig. 3f

F ig. 5 Lis a side elevation of the vehicle showing the invention applied.

Fig. 6 is' an elevation representing a pair of springs as applied at an end of the vehiele. j i

rlhe inventioi'fcomprises essentially three 12 connected together at their upper 'ends and spaced apartto form a cylinder pocket for .the intermediate lower sliding cylinder 11. lThe sliding cylinder 11 incloseswith xthe inner cylinder 12, a space which is div12 and 11 is suitably packed 'to prevent eX- cessive leakage from chamber 14. Preferably, I- employ a ring 18 screwing into the lower end of the inner cylinder 12 and act ing to support a cup leather 19, which proof the sliding cylinder 11. j

A flat steel coil spring 2O encircles the lower end of the ring 18 and acts eXpan sively against the cupjleather to ,hold it in sliding Contact with cylinder 11; a collar Y 21 serving to keep the spring in place on the ring. YNo particular claim is made to this coil spring in the present application,

fas it forms the subject-matter of an independent invention.

Experience shows that so little oil escapes past the .sliding joint 19 that it is necessary to apply a lubricant from time to time throughv an oil cup 22 in order to provide sufficient lubrication between the sliding cyl-I inder and the outer cylinder 10; a packing jects below and over-hangs the endl of the inner cylinder 12 and lies against the wall other to reduce the space therein to 'aminis compressed to li 23 preventing the escape ofthis added lubricant from between the cylinders. A

Operation.

usually connected with the air springs byv .means of a shackle 26 well known in the Lubrication'to the shackle ybearing 27 is taken `care of by means of 2, leading from the bearing upwardly and outwardly through the head 17 to the sliding joint between thev cylinders 10-11; lubrication from these cylinders being sufficient to lubricate the shackle bearing.

The cylinders when charged with oil are Y or telescoped onewithin the mum. That is, the piston 15-is shoved up as far as possible into the cylinder 12. This inward telescopic action obviously decreases the cubic contents of chamber 14. Oil is then charged into the cylinders to fill chamber 14 and to leave a small quantity vof oil also standing in chamber 13 over the pistonv packing. Naturally any elongation ofthe cylinders will result in enlarging the chamber 14,'due to the difference in diameters lof the cylinders 11-12 below the piston. This mcrease in volumetric capacity of chamber '14 on elongation or rebound is taken advantage of by check recoil as will be later described.

After being charged withhoil as'above described, suitable air pressure to support the load is'supplied tochamber 13 through an appropriate opening in the top 'controlled by cap 31.

Chamber 13 is the cushion chamber' and chamber 14 below the piston in addition to forming an oil reservoir, has the purpose of forming a vacuum chamber acting on the under-side' of the piston against rebound of the spring following a sudden compression of the air in the a consequent reboundof the parts, as pressure on the compressed air is relieved. In other words, when the apparatus starts to eXpand,-due to rebound, there`is a countereifeet produced due to the presence of the piston within the cylinder, so that when the upper cylinder 4is moved upwardly on rebound it enla/rges the space below the piston and reduces a vacuum therein'which tends il', the portion of the load to which the lower cylinder is attached, and by that much -tending to pull down the portion of the rebounding lead lto which the upper cylinder is attached.

air in the upper -cylinder.

upper cushion chamber and' j In short, the vehicle body, which is lconnected with the upper cylinder, i

nalaat/ix and the chasis which is attached to the lower cylinder, willsbe causedby' the 'present con struction, to be pulled toward each other;

' lengthen the air spring, due to the natural' elasticityof the compressed air in the upper cylinder, produces a counter-force to create vvacuum in the lower chamber tending to drawthe parts together again; the point of approach of the body and chasis being determined by the volume of the compressed forces of vacuumin one chamber and expansion in the. other, tends to bring the vibrating parts quickly to a station of rest.

Any replenishment of the oil seal above the piston is efected by the displacement in the lower chamber 14 below the piston due to the telescopic action of the cylinders; any excess of accumulation of oil in the lower 'chamber finding an outlet upwardly around the packing of the piston 15.

Depending from the underside of the piston 1'5 is a flange member 28 adapted 4to have a fairly snug telescoping lit with collar 18 on the extreme extension movement of the upper-and lower cylinders; the object being to form between the flange 28 and the imperforate outer wall of a spider 29 to which it is attached, an oil. trap which acts as a dash These opposin g v pot to check any tendency of the piston to impinge forcibly against the ring 18; there being 'provided a bleed port 30 in the wall of the iiange 28 to allow for the slow escape of the oil and relieve any tendency of a sudden check of the moving parts by the entrapping ofthe oil in the dash pot.

An essential'feature to the practical sur cess 0f this springis that when the cylinders are telescopedV to their innermost dimensions the chamber 14 below the piston should be entirely filled with oil, or other liquid, so that there is practically no air or other elastic medium in chamber 14. The amount 'of sealing liquid inchamber 13 over the piston need only be such as to insure a liquid sealing joint for the 'piston packing.

he presence kof air 'below the piston is inimical to the successful operation of the device; the entire cushioning action being in the upper chamber; the'lower chamber being essentiallya recoil check and a source of oil` Thus a condition prevails wherein the lower chamber 1s mamtalned normally at l l y ,Lainate .Y www atmospheric pressure or below, while the upper chamber is sustained under high pressure, yet at long intervals and for an instant ing of' the piston which is the only meansfoif communicationbetween the two chambers.

A very short-lipped cup leather is used forV the piston packing so that the pressure' of the fluid above thepiston is suiiicient to keep.

the sliding joint between the piston and the cylinder tight. A l

rIhe foregoing construction 'provides a simple, self-contained, stanch automatic air spring with a 'minimuml of moving' parts.

It is manifest thatvarious changes in details of construction may be made without departing-from the principle of the inven-- tion.

Having thus I claim and desire tojsecu're by Letters Patl. In ani-air spring comprising in combination telescoping cylinders Yclosed at their outer ends and inclosing a space, a solid piston vcarried by the lower cylinder and as to fill the lower chamber and to submerge-v the 4piston packing when the-twol cylinders are telescoped to their innermost limits, an

annular packing carried by the inner cylinder and overhanging the lower end of the latter and in. sliding contact withthe outer cylinder and submerged inthe liquid in the lower chamber andadapted to1 prevent leakp age from the cylinders, the Iupper chamber forming a compression and cushioning chamber and the lower chamber acting on the extension of the`cyl1nders to create a vacuum in the lower chamber to counteract the expansive action of the air spring.

2. In an hir spring comprising'bin combination telescoping cylinders closed at their outer ends and inclosing a space, a solid piston carried by `the lower cylinder and working inside the upper cylinder .and di-.

as to fill the lower chamber andto submerge the piston packing when the two cylinders are telescoped to their innermost limits, an

annular lpacking carried by the inner cylinder and overhanging the lower end of the latter and in sliding contact with the Aouter cylinder and submerged in the liquid inthe described Imy invention what lower chamber and adapted to prevent leakage. from the cylinders, the upper chamberforming a' compression..and cushioning chamber and the lower chamber acting onthe `extension of the cylinders to create a .vacuum in the lower chamber to' counteract the expansive action of the air spring, and a dash pot connected with the piston and co-acting with the part on the cylinder in which the piston slides to check recoil. 3. In an air spring comprising telescopiiig inner upper, and lower outer, cylinders closed at their outer ends and inclosing a space, a piston working in the upper cylinder carried by the lower cylinder, andl di-` viding said space into an upper f chamber for compressible fluid and a lower chamber tel for incompressible iluid,.a packingfor the l sliding joint between the cylinders, a ring on the lower end' of the inner cylinder for retaining said packing in place andA forining also a stop cooperating with thepiston to limit the separating movement of said cylinders, and means forming a dash-pot between the piston and ring for restraining outward movement of the cylinders when they7 approach their limit of separation.

4. In an air spring comprising telescoping cylinders closed at their outer ends and inclosing a space,v a piston working in lthe upper cylinder carried by the lower cylinder, a packing for the sliding joint between the cylinders, a dash pot withA which the piston co-acts to check recoil, said dash pot being below the piston and cooperating with said packing means.

5. In an' air spring, the combination of telescoping cylinders closed at their outer ends and inclosing a space, a piston carried by the lower cylinderand `workinginside the upper cylinder dividingsaid space into two chambers which are out of communication with each other except for such leakage as may take place around the 1 piston packing, a body of oil contained within the cylinders of suchquantity that when the cylinders areiitelescoped to theirinnermost limits the 4lower chamber is iilled with oil, and the vpiston packing in theupper chamber-is submerged to form an oil seal leaving an air cushion space above the oil in the uppercylinder, and -a packed sliding joint between the cylinders, the upper chamber 'forming a compression and cushioning chamber, and the lower chamber acting on the extension of Vthe cylinders to create a vacuum in the lower chamber to counteract the `expansive action'of the air spring. V 6. In an air spring, the combination of telescoping cylinders closed at their outer ends and inclosing `a space, a piston carried by the lower cylinder and working inside the upper cylinder dividing said space into two chambers which are out of communication with each other except for such leaklili iat

age as may take place around the piston vvacuum in the lo-Wer chamber to counterpacking, a body of oil contained Within the Vact the expansive action of the air spring,

i vcylinders of -such quantity that .when .the and an annulus connected and movable with cylinders are telescoped to their innermost the-piston for (3o-acting with an annular limits the lower chamber is filled With oil part onthe upper cylinder and below the v and the piston packing in the upper cham p1ston to form a dash pot to check recoil.

ber is submerged to form an oil seal leaving In testimony whereof I have hereunto set an f air cushion /space above the oil in the my hand in the presence 4of two subscribing upper cylinder,' 'nd a packed sliding vjoint Witnesses.

betweeny the cyjrnders, the upper chamber LUCIEN R. GRUSS. y

forming a compression and cushioning Vitnesses:

chamber, and the lower chamber acting on W. W. HEALEY,`

the extensionv of the cylinders to create a M; E. EWING. 

